Sectional endless belt



y 1940- H. P. KIRCHNER 2,209,059

SECTIONAL ENDLESS BELT Filed Feb. 24, 1938 fly. 1

IN VENTOR.

HENRY P KIRCHNER.

rrm mrv Patented July 23, 1940 PATENT OFF ICE SECTIONAL ENDLESS BELT Henry P. Kirchner, Niagara Falls, N. Y.,. assignor to The Carborundum Company, Niagara Falls, N. Y., a corporation of Delaware Application February 24, 1938, Serial No. 192,205

4 Claims.

This invention relates to abrasive belts. It relates particularly to belts for polishing metal sheets which are wider than the abrasive sheet material now commercially available.

Abrasive belts heretofore used for polishing large sheets of metal have been made by preparing a paste of adhesive and abrasive grain and smearing it on a backing of heavy canvas.

This type of belt has been generally unsatisfactory. The adhesive cracked easily when the belt was stretched over a pulley, allowing chunks of abrasive and adhesive to fall off and become caught between the belt and the work, resulting in objectionable scratches. The abrasive was substantially embedded in the adhesive thereby giving a low cutting rate, and the abrasive layer was not of uniform thickness.

Because of these and other disadvantages, various attempts have been made to make wide belts from ordinary sheet abrasive material, by splicing together sections of the material cut lengthwise from the roll. In these attempts, the sections of abrasive material were mounted on a liner of canvas or other similar material by means of an adhesive.

While these composite belts proved to be somewhat more satisfactory than belts made by the old method, many complaints were received from the trade because the abrasive sections came loose on the liner and because the weight and cost of the belt was high.

Attempts have also been made to make up wide belts of segments adhesively attached to one another without the use of a liner. These have been unsuccessful because, if the joints ran across the material at right angles to the curvature of the belt, the joints bumped as they passed over the pulleys and the finish was unsatisfactory. If the joints ran at an angle to the curvature of the belt, but parallel to one another, the belts would run oil the pulleys in a few revolutions. Various means were tried to counteract this running off tendency such as additional rollers or tensioning means, but without success.

The improved belt disclosed and claimed herein overcomes the disadvantages set forth above. It is easily and economically manufactured, its weight is not substantially greater than a one piece belt of the same size, and trouble due to separation of the sections and running oil has been eliminated.

The invention will be described in connection with the accompanying drawing in which like reference numerals designate like elements in the following specification.

Figure 1 illustrates diagrammatically an example of abrading apparatus for use with the belt of the present invention;

Figure 2 shows a section of abrasive belt made in accordance with the present invention. 5

Figure 3 is a section (highly magnified) along the line III-IH of Figure 2 showing the adhesive oin Referring to the drawing, the apparatus shown in Figure 1, for use with which the new belt is 10 particularly adapted, comprises pulleys ill, H and it, one or more of which is driven by some suitable means. The belt I3 is pressed on to the work it by the pulley l2. The work sheet is supported by the reciprocating table it. 15

Figure 2. shows a section of abrasive belt made up according to the present invention. The belt consists of a number of trapezoidally shaped segments it cemented to one another along their non-parallel edges. 20

The trapezoidal segments are cut lengthwise from a roll of regular stock abrasive paper or cloth having the proper grit size. The length of each segment is determined, of course, by the width of belt desired. It is obvious that a belt of any width may be made by this method.

The segments may be regular or irregular in size and shape, but in order for the belt to run true on the pulleys, adjacent lines of juncture must be at an angle to each other, and the lines of juncture between segments should run diagonal to the longitudinal axis of the belt. By this arrangement, less strain is put on the adhesive joints as the belt passes around the pulley and there is less of a tendency for the joints to "bump as they pass over the pulley than if the joints ran at right angles to the longitudinal axis of the belt.

The preferred construction is that shown in Figure 2. The segments l6 have the shape of an isosceles trapezoid, that is, two edges of the segment are parallel and the non-parallel edges are equal in length.

It has been found that a belt made from segments of this shape will run absolutely true on the pulleys, and no liner is required; nor are any extra pulleys, tensioning means, etc. required.

It is desired to point out however that this shape may be departed irom somewhat without seriously affecting the operation of the belt. For instance, the segments may have the shape of an isosceles triangle, or, they may have the shape of a non-isoscelestriangle or trapezoid.

Figure 3 shows a magnified view of the adhesive 55 joint employed in the arrangement shown in Figure 2.

As is apparent from the drawing, the abrasive and glue has been skived off the web along the edges and a'layer of suitable cement I! has been applied.

The adhesive joint is cured by the application of heat and/or pressure; injury to' the abrasive being avoided by use of a resilient pad during the pressing operation.

Because the belt made in accordance with the invention requires no liner, it is lighter in weight and far less costly to produce than conventional sectional belts employing liners.

Having thus described the invention, I claim: 1. An unlined abrasive belt consisting of a plurality of trapezoidally shaped segments of abrasive paper adhesively joined to one another along their non-parallel edges.

2. An unlined abrasive belt consisting of a. plurality of similar segments of abrasive sheet material adhesively attached to one another, the joints between adjacent segments being nonparallel whereby the belt is caused to run true on the pulleys.

3. An unlined abrasive belt consisting of a plurality of segments of abrasive sheet material adhesively attached to one another, said segments having the shape of an isosceles trapezoid.

4. An unlined abrasive belt substantially wider than the width of the abrasive sheet material from which it is made and consisting of a plurality of segments of abrasive sheet material adhesively attached to one another, the joints between adjacent segments being non-parallel whereby the belt is caused to runtrue on the pulleys.

HENRY P. KIRCHNER. 

